Cache issues in vexpress cpu shutdown (regression in 3.10)

[catalin.marinas@arm.com (Catalin Marinas)]

On Wed, Jun 05, 2013 at 08:08:53PM +0100, Russell King - ARM Linux wrote:
> On Wed, Jun 05, 2013 at 01:05:39PM +0100, Lorenzo Pieralisi wrote:
> > There is an A9 errata (fixed in r1p0) whereby CLIDR[23:21] reads as 0
> > where it should read as 3'b001, so basically flush_cache_louis is not
> > flushing anything. If that's the problem, either we add a generic fix
> > in v7 cache assembly or we just fix it in platform code (by calling
> > flush_cache_all()), since there should not be many pre-r1p0 around.
> > 
> > Please let me know what you think.
> 
> If we're providing a flush_cache_louis() function, then it better do
> what it says or be removed.  So the right solution is to fix the
> function rather than working around it, because over time we'll only
> add more calls to flush_cache_louis() and it'll become a stumbling
> block.

I think at some point we should define this unification level in the DT,
maybe together with the CPU topology. We use LoUIS because it seems to
be the right thing on all the existing platforms but it's nothing in the
architecture that says LoUIS is the right level of flushing for the
CPU-local caches.

-- 
Catalin